Intravascular device utilizing fluid to extract occlusive material

ABSTRACT

An intravascular device and associated system which utilizes pressurized fluid to extract occlusive material. The device and system includes several unique features which provide desirable advantages over prior art devices. For example, the device is particularly suitable for removing occlusive material which is diffuse, friable, grumous-like, paste-like, granular, and/or chunky. The device includes independently movable fluid input and fluid output tubes and may be advanced over a guide wire. The fluid port holes are located immediately adjacent the distal end of the fluid output tube so as to engage the occlusive material without the need to first traverse the occlusive material with the device. The system utilizes a unique constant volume pump and associated pressure sensors to maintain balanced flow and immediately detect and correct conditions which may cause clinical complications.

This is a continuation of application Ser. No. 08/269,715, filed Jul. 1,1994 now abandoned.

FIELD OF THE INVENTION

The present invention generally relates to intravascular devices for theremoval of occlusive material. More specifically, the present inventionrelates to intravascular devices utilizing fluid to extract occlusivematerial and methods of use thereof. Those skilled in the art willrecognize the benefits of applying the present invention to similarfields not discussed herein.

BACKGROUND OF THE INVENTION

A wide variety of therapeutic techniques have been developed to corrector inhibit vascular diseases. Coronary artery disease (CAD), forexample, is an adverse condition of the heart in which the blood flow tothe heart muscle is partially or totally restricted by occlusivematerial in the coronary arteries is which narrows the blood flow lumen.The occlusive materials deprive portions of the heart muscle ofessential oxygenated blood.

CAD may be treated by a surgical technique referred to as coronaryartery bypass graft (CABG) surgery. This surgical procedure involvessupplementing blood flow to the heart muscle by grafting non-nativeconduit such as a saphenous vein graff (SVG) to the heart. A first endof the SVG is connected to the ascending aorta (proximal to theocclusive material) and the other end is connected to the artery distalof the occlusive material. Although this technique has been useful fortreating CAD in native coronary arteries, it is not uncommon forocclusive material to form over time in the SVG thereby necessitatingadditional therapy. Typically, the nature of the occlusive material inthe new SVG may be diffuse, friable, grumous-like, paste-like, granular,and/or chunky.

Percutaneous translumenal coronary angioplasty (PTCA) has gained wideacceptance as an effective and less invasive alternative to CABG surgeryin certain patient groups. The PTCA procedure involves the use of anangioplasty balloon catheter, several types of which are well known inthe art. The balloon catheter is inserted into the body via the femoralartery and navigated to the coronary arteries assisted by a guidecatheter and (usually) a guide wire. The balloon is positioned acrossthe restriction in the artery and subsequently inflated. The inflatedballoon widens the restriction and restores blood flow to portions ofthe heart muscle previously deprived of oxygenated blood.

Although balloon PTCA has been demonstrated to be clinically effectivein treating a wide variety of vascular restrictions, there arealternative devices and techniques which are specially adapted to treatlesions with complex morphology and/or unique pathology. For example,SVGs commonly contain abnormal deposits which are diffuse, degenerated,and thrombus-containing. Because treating an SVG lesions with balloonPTCA has an unfavorably high incidence of distal embolization,alternative therapies such as atherectomy have been favored.

Atherectomy (or thrombectomy) is an alternative to balloon PTCA andtargets specific types of lesion morphology and pathology. Atherectomy,as distinguished from balloon PTCA, removes the occlusive material fromthe local vasculature rather than molding or reshaping the restrictionby compression. While some prior art atherectomy devices have beenspecifically indicated to be effective for treating certain types ofdiseased SVGs, the incidence of complications (e.g. distal coronaryartery embolization, cerebral embolization via the aorta) has beenreported to be sub-optimally high. Thus, there is a need for an improvedatherectomy or thrombectomy device for the removal occlusive material,particularly in friable, diffusely diseased SVGs.

Several prior art atherectomy or thrombectomy devices utilize conceptsof fluid jets to remove occlusive material. For example, EPO Application470,781 A1 to Drasler discloses a device which uses high pressure waterjets to remove occlusive material. The high pressure water jet isdirected proximally to dislodge and emulsify thrombus. However, becauseof the high pressures associated with this device and the correspondingrisk of damage to the vessel wall if exposed to the high pressure jet,the water jet is only exposed through a laterally facing window in aprotective housing. Since the effective cutting area is limited to thesize of the window, multiple passes are required to remove occlusivematerial deposited around the inner circumference of the vessel.Furthermore, because the device utilizes a prospective housing, aportion of the device must first traverse the occlusion before the waterjet is able to dislodge and emulsify the occlusive material. Thisunnecessarily increases the risk of distal embolization and increasesthe difficulty in crossing a tight occlusion.

A similar high pressure water jet atherectomy device is disclosed in EPOApplication 485,133 A1 to Drasler. This water jet atherectomy devicealso utilizes a very high pressure (more than 3,500 psi) water jet whichis directed distally or proximally within a protective housing. Thisdevice further includes a biasing balloon which permits asymmetric ordirectional atherectomy. Once again, because of the high pressuresassociated with this device and the corresponding risk of damage to thevessel wall if exposed to the high pressure, the cutting area isessentially limited to the open window in the protective housing. Sincethe effective cutting area is limited to the size of the window,multiple passes are required to remove occlusive material depositedaround the inner circumference of the vessel. Furthermore, because thedevice utilizes a protective housing, a portion of the device must firsttraverse the occlusion before the water jet is able to dislodge andemulsify the occlusive material. As stated earlier, this unnecessarilyincreases the risk of distal embolization and increases the difficultyin crossing a tight occlusion.

A further example of a high pressure water jet atherectomy device isdisclosed in EPO Application 489,496 A1 to Drasler. This water jetatherectomy device also utilizes a very high pressure (more than 3,500psi) water jet directed distally to dislodge and emulsify thrombus. Thejet stream is directed distally to permit the ablation of a totalocclusion without requiring the distal end of the device to first crossthe occlusion. However, because of the distally directed high pressurewater jet used in this device, damage to the vessel wall is risked forlack of a protective shield. Furthermore, the distally directed waterjet tends to flush the dislodged material in a distal direction whichmay result in undesirable embolization.

Another pressurized (440 psi minimum pressure source) fluid device isdisclosed in U.S. Pat. No. 4,690,672 to Veltrup. This device directs afluid stream proximally into a mouth of a suction tube and removesunwanted material when the material is in juxtaposition with the mouthof the suction tube. Similar disadvantages are associated with thisdevice. For example, the cutting diameter is essentially limited to thesize of the opening, which is less than the diameter of the cathetershaft. Additionally, no occluding balloon is provided which increasesthe risk of simply draining blood from the occluded vessel. Also, noguide wire is provided to guide the catheter within the vasculature,thus intravascular navigation would be significantly limited.

A further limitation common to several of the above-cited fluid jetatherectomy devices is that the fluid input lumen and the effluent lumenare longitudinally fixed relative to each other. More specifically, thefluid input lumen and the effluent lumen can not be longitudinally movedindependently. This requires the relatively large effluent lumen to beadvanced along with the fluid input lumen. Since the effluent lumen isrelatively large and stiff, the distance the device can be advanced intotortuous and/or small diameter vessels is limited. Additionally, thefluid input lumen can not be retracted into the extraction lumen toclean up clogging debris.

In view of the unresolved disadvantages of each of these devices, it isdesirable to have a device which utilizes a relatively low fluidpressure to minimize the risk of causing damage to the vessel wall. Itis also desirable to have a device which directs fluid laterally ratherthan proximally or distally. Laterally directed fluid allows the deviceto dislodge material immediately adjacent the distal end of the devicewithout first traversing the occlusion and also reduces the risk ofdistal embolization. It is further desirable to have a device whichutilizes independently movable fluid input and fluid extraction lumensto maximize vascular accessibility and remove clogs that form in theextraction lumen.

SUMMARY OF THE INVENTION

The present invention overcomes the competing disadvantages of the priorart in a novel and non-obvious manner. One embodiment of the presentinvention is a fluid system used to extract vascular occlusion material,and includes a long catheter shaft having a fluid input lumen and anextraction lumen extending therethrough. A pressurized fluid source isconnected to the proximal end of the shaft and is in fluid communicationwith the fluid input lumen. A pressurized fluid collector is connectedto the proximal end of the shaft and is in fluid communication with theextraction lumen. A nozzle is attached to the distal end of the shaftand is in fluid communication with the fluid input lumen. A controlsystem is operatively connected to and controls the pressurized fluidsource and the pressurized fluid collector as a function of fluiddynamic parameters in the fluid input lumen and the extraction lumen.

Another embodiment of the present invention is a fluid system whichincludes an elongate extraction tube having an extraction lumenextending therethrough and a fluid input tube coextending with theextraction tube and longitudinally movable relative thereto. The fluidinput tube has a fluid input lumen extending therethrough. A pressurizedfluid source is connected to the proximal end of the fluid input tubeand is in fluid communication with the fluid input lumen. A pressurizedfluid collector is connected to the proximal end of the extraction tubeand is in fluid communication with the extraction lumen. A guide wire ispositioned so as to coextend with the fluid input tube and is alsolongitudinally movable relative thereto. A nozzle is connected to thedistal end of the fluid input tube and is in fluid communication withthe fluid input lumen.

Yet another embodiment of the present invention is a fluid systemincluding an elongate catheter shaft having a fluid input lumen and anextraction lumen extending therethrough. A pressurized fluid source isconnected to the proximal end of the shaft and is in fluid communicationwith the fluid input lumen. A pressurized fluid collector is connectedto the proximal end of the shaft and is in fluid communication with theextraction lumen. A nozzle is attached to the distal end of the shaftand is in fluid communication with the fluid input lumen. At least oneport hole is located about the circumference of the nozzle and isdirected laterally such that the axis of the hole is at an angle ofabout 90 degrees with the longitudinal axis of the shaft. The fluidexiting the port hole defines a cutting diameter which is greater thanthe outside diameter of the catheter shaft adjacent to the nozzle.

A further embodiment of the present invention is a fluid system for theextraction of vascular occluding material wherein the vasculature has afirst pressure zone with a first pressure (P1) proximal to the occludingmaterial, and a second pressure zone with a second pressure (P2)adjacent the occluding material. The fluid system includes a cathetershaft having a fluid input lumen and an extraction lumen extendingtherethrough. A pressurized fluid source is connected to the proximalend of the shaft and is in fluid communication with the fluid inputlumen. A pressurized fluid collector is connected to the proximal end ofthe shaft and is in fluid communication with the extraction lumen. Anozzle is attached to the distal end of the shaft and is in fluidcommunication with the fluid input lumen. A control system controls thepressurized fluid source and the pressurized fluid collector as afunction of at least one of the pressures (P1 or P2).

In practice, a method of using a fluid system for the extraction ofvascular occluding material wherein the device includes an extractiontube having an extraction lumen extending therethrough, a fluid inputtube having a fluid input lumen extending therethrough and beinglongitudinally movable relative to the extraction tube, a pressurizedfluid source connected to the proximal end of the fluid input tube andin fluid communication with the fluid input lumen, a pressurized fluidcollector connected to the proximal end of the extraction tube and influid communication with the extraction lumen, a guide wire coextendingwith the fluid input tube and longitudinally movable relative thereto,and a nozzle connected to the distal end of the fluid input tube and influid communication with the fluid input lumen, the method of useincludes the steps of: (1) Inserting the guide wire into the fluid inputtube, (2) advancing the guide wire, the fluid input tube and theextraction tube into a vascular lumen, (3) positioning the distal end ofthe extraction tube proximal to an occlusion to be removed, (4)positioning the distal end of the fluid input tube adjacent theocclusion to be removed, and (5) activating the pressurized fluid sourceand the pressurized fluid collector.

While the disclosure focuses on intravascular fluid devices, one skilledin the art will recognize that the invention may be incorporated intoother apparatus and methods of use not discussed herein. Furthermore, inaddition to the advantages described, other advantages of the presentinvention may be appreciated without departing from the spirit of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1a is a plan view of a first embodiment of the present invention.

FIG. 1b is a plan view of a second embodiment of the present invention.

FIG. 1c is a plan view of a third embodiment of the present invention.

FIG. 2a is a longitudinally partially sectioned view of a firstembodiment of a catheter of the present invention.

FIG. 2b is a longitudinally partially sectioned view of a secondembodiment of a catheter of the present invention.

FIG. 3 is a cross sectional view taken at 3--3 in FIG. 2a and at 3--3 inFIG. 2b.

FIG. 4a is a cross sectional view of a first embodiment of a port tubeof the present invention taken at 4--4 in FIG. 2a and 4--4 in FIG. 2b.

FIG. 4b is cross sectional view of a second embodiment of a port tube ofthe present invention taken at 4--4 in FIG. 2a and at 4--4 in FIG. 2b.

FIG. 4c is a cross sectional view of a third embodiment of a port tubeof the present invention taken at 4--4 in FIG. 2a and at 4--4 in FIG.2b.

FIG. 4d is a cross sectional view of a fourth embodiment of a port tubeof the present invention taken at 4--4 in FIG. 2a and at 4--4 in FIG.2b.

FIG. 4e is a cross sectional view of a fifth embodiment of a port tubeof the present invention taken at 4--4 in FIG. 2a and at 4--4 in FIG.2b.

FIG. 5 is a longitudinally sectioned view of a port tube manifold of thepresent invention.

FIG. 6 is a longitudinally sectioned view of an extraction tube manifoldof the present invention.

FIG. 7 is a longitudinally partially sectioned view of a modulator valveof the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description should be read with reference to thedrawings in which like elements in different figures are numberedidentically.

Specific materials, dimensions and manufacturing processes are providedfor selected design elements. Those design elements which do not havespecific materials, dimensions or manufacturing process identified,employ that which is well known to those skilled in the field of theinvention. In addition, those skilled in the art will recognize many ofthe materials, dimensions and manufacturing processes identified areexemplary, for which suitable alternatives may be utilized.

Referring to FIG. 1a, a plan view of a first embodiment of the fluidsystem 10 is shown. The basic fluid system 10 includes a catheter system11, a pressurized fluid source 15, a pressurized fluid collector 17, anda control system 16. The catheter system 11 includes a port tube 12(also referred to as fluid input tube), an aspiration tube 13 (alsoreferred to as extraction tube), and a guide wire 14. Catheter system 11may be used in combination with a guide catheter 26 (as shown in FIGS.2a and 2b) to facilitate navigation in the coronary artery system. Thepressurized fluid source 15 operates between about 1 and 2500 psi,preferably 500 and 1500 psi, and causes pressurized fluid to be suppliedinto the port tube 12 and exit its distal end through port holes 32. Thepressurized fluid is preferably a saline solution but may also includetherapeutic agents, heparin, and/or an abrasive suspension. Thepressurized fluid collector 17, by way of extraction tube 13, removesthe fluid exiting port holes 32 as well as any dislodged occlusivematerial. The pressurized fluid collector 17 may operate at pressuresless than atmospheric pressure (i.e. a vacuum) or at pressures nearatmospheric pressure. The control system 16 maintains volumetric flowequilibrium between the pressurized fluid source 15 and the pressurizedfluid collector 17 so as to prevent distal embolization, vessel ruptureand vessel collapse. A detailed description of the control system 16 andthe alternate fluid systems 10 shown in FIGS. 1b and 1c is discussedafter the following detailed description of catheter system 11.

The catheter system includes extraction tube 13, as best shown in FIG.2a, which in turn includes an occluding balloon 27 mounted on its distalend and in fluid communication with the balloon inflation lumen 28. Theoccluding balloon 27 serves to isolate the vascular site and preventblood from flowing distally thereof and also prevents retrograde flow ofdislodged debris. An occluding balloon (not shown) may also be includedon the port tube 12 to further isolate the treatment site. Extractiontube 13 further includes an extraction lumen 29 extending along itsentire length. An aspiration window 30 is positioned immediatelyproximal of the distal annular opening defined between the port tube 12and the extraction tube 13. Preferably two aspiration windows 30 areutilized and placed on opposite sides of the extraction tube 13.Aspiration window 30 provides additional surface area so as toaccommodate dislodged occlusive material of a size which may be largerthan the annular opening between the port tube 12 and distal end of theaspiration tube 13. Additionally, aspiration window 30 provides a safetymechanism whereby if the annular opening at the distal end of theextraction tube 13 becomes clogged, fluid may still be removed throughthe aspiration window 30 and into the extraction lumen 29. This reducesthe risk of causing distal embolization and vascular rupture. Extractiontube 13 also includes a radiopaque marker band 31 secured to its distalend. The radiopaque marker band 31 allows the physician toradiographically determine the position of the catheter system 11 and inparticular, the vascular extraction tube 13. In addition, a radiopaquemarker band (not shown) may be located on the distal end of the porttube 12, substantially as described above.

Extraction tube 13 is preferably made of a dual-lumen extruded polymerwith an outer diameter of about 2.34 mm, a balloon inflation lumen 28diameter of about 2.46 mm, and an extraction lumen 29 cross-sectionalarea of about 3.0 mm². The extraction tube 13 is preferably made of apolymer such as high density polyethylene, a blend of low density andhigh density polyethylene, or a blend of a polyetheter/polyamidepolyester and high density polyethylene, and may include tapers alongits length of preferably 133 cm. Occluding balloon 27 is preferably madeof a thin-walled polymer such as an ionomer and has a deflated andwrapped outer diameter of 0.097 inches and a maximum expanded diameterof 6 mm at preferably 28 psi. The guide catheter 26 inside diameter mustbe sized to provide sufficient clearance around the deflated occludingballoon 27 to allow for the injection of contrast fluid. Occludingballoon 27 is preferably secured to the extraction tube 13 by means of asuitable adhesive such as a two-part urethane or by means of a thermalbonding process. Aspiration window 30 preferably includes twooppositely-facing windows with a length of 2.5 mm and a height of 2 mm.The aspiration window 30 is preferably formed in the extraction tube 13by means of a punching process. Marker band 31 is preferably made of aradiopaque alloy such as 90% platinum+10% iridium, but other suitabledense metals such as gold, or platinum may be employed. Radiopaquemarker band 31 preferably has a length of 1.3 mm, an outer diameter of2.1 mm, and an inner diameter of 2.0 mm. The radiopaque marker band 31is secured to the inner surface of the extraction tube 13 by a suitableadhesive such as a two-part epoxy.

Referring to FIG. 2b, an alternate embodiment of the extraction tube 13is shown. All aspects of the aspiration tube 13 are identical to thosedescribed with reference to FIG. 2a, with the exception of bypass valve33 which is used either in place of or in addition to aspiration window30. The bypass valve 33 incorporates a hinged flap which allows fluid topass in one direction. The bypass valve may be located on either side(interior/exterior) of the extraction tube 13 or on both sides. In theevent that excess fluid is being extracted, bypass valve 33 allows fluid(probably blood) to enter the extraction lumen 29 in order to avoidvessel collapse. Alternatively, in the event that excess fluid is beingdelivered or the extraction lumen 29 becomes clogged, the bypass valve33 allows fluid to escape the extraction lumen 29 in order to avoidvessel rupture and/or distal embolization. Thus, bypass valve 33 reducesthe potential for distal embolization, vascular collapse and vascularrupture.

Referring to FIGS. 2a, 2b and 4a, a port tube 12 is shown which isslidably disposed in extraction tube 13. A guide wire is also slidablydisposed in extraction tube 13 either adjacent to or within port tube12. The port tube 12 may be made of a dual lumen extrusion and includesa fluid input lumen 34 and a guide wire lumen 35 as best shown in FIG.4a. The port tube 12 is preferably made of extruded high densitypolyethylene wrapped with stainless steel wire coated with polyurethaneand has an outer diameter of 1.3 mm, a guide wire lumen 35 diameter of0.5 mm, and a fluid input lumen 34 cross-sectional area of 0.4 mm². Porttube 12 includes a plurality of port holes 32 (collectively referred toas a nozzle) which are formed in the distal end of the port tube 12 by apunching process or a drilling process. The distal end of fluid inputlumen 34 is plugged with a suitable adhesive such as two-part urethaneto force pressurized fluid through port holes 32. The nozzle may be madeintegral with the port tube 12 as discussed or may be made a separateelement attached to the distal end of port tube 12. Port holes 32 arepreferably spaced in three circumferential rows with preferably four toeight holes per row. The number of rows and number of holes per row canbe adjusted to affect the size and geometry of the spray field. Portholes 32 preferably have an inner diameter of 0.6 mm and are laterallydirected at a 90-degree angle relative to the longitudinal axis of theport tube 12 and directed at a 60-degree angle relative to a tangentline on the outer surface of the port tube 12. The laterally-directedports 32 allow the pressurized fluid exiting through the port holes 32to engage the occlusive material without the need to substantiallytraverse the occlusion with the distal end of port tube 12. In addition,since the port holes 32 are not directed distally, the momentum of thepressurized fluid does not force the dislodged occlusive materialdistally. Furthermore, because port holes 32 are directed at an angle toa tangent line on the outer surface of port tube 12, the impact ofpressurized fluid against the vessel wall is diverted and thus thepotential for trauma to the vessel wall is minimized. This angularorientation of port holes 32 also creates a spiral flow pattern whichadds to the effect of the pressurized fluid.

With reference now to FIG. 4b, a second embodiment of the port tube 12is shown with port holes 32 directed proximally at an acute anglerelative to the longitudinal axis of the port tube 12 and orthogonallyrelative to a tangent line on the outer surface of port tube 12. Thisorientation of port holes 32 causes the pressurized fluid to forcedislodged occlusive material proximally toward the extraction tube 13.In addition, since port holes 32 are directed at an acute angle relativeto the longitudinal axis of the port tube 12, the impact of pressurizedfluid against the vessel wall is diverted and thus the potential fortrauma to the vessel wall is minimized.

FIG. 4c shows a third embodiment of the port tube 12. In thisembodiment, port holes 32 are arranged to provide acircumferentially-even distribution of pressurized fluid. As compared tothe embodiments shown in FIGS. 4a and 4b, the embodiment as shown inFIG. 4c eliminates the "blind spot" created by the presence of guidewire lumen 35 and guide wire 14. Preferably six port holes 32 arearranged in each circumferential row.

FIG. 4d shows a fourth embodiment of the port tube 12 which includes aninner tube 36a and an outer tube 36b. The inner tube 36a is dimensionedto accommodate a guide wire 14 and is coaxially disposed within outertube 36b. The outer tube 36b includes a plurality of port holes 32equally spaced in preferably three rows of eight holes per row. Bothinner tube 36a and outer tube 36b are made from an extruded polymer suchas high density polyethylene. The inner diameter of inner tube 36a isthe same as the diameter of guide wire lumen 35 as discussed above. Thecross-sectional area of fluid input lumen 34 is substantially the sameas described above with reference to FIG. 4a. The coaxial arrangement ofinner tube 36a and outer tube 36b provides uniform lateral flexibility.

Referring now to FIG. 4e, a fifth embodiment of the port tube 12 isshown. In this embodiment, the guide wire 14 coextends with the exteriorof port tube 12. This embodiment reduces the overall outer diameter ofport tube 12 while maintaining similar flow characteristics in the fluidinput lumen 34 as compared to the embodiments discussed above. The porttube 12 may include guide loops (not shown) along its length tofacilitate advancement along the guide wire 14.

With reference to FIG. 4f, a sixth embodiment of the port tube 12 isshown. The port tube embodiment as shown in FIG. 4f includes a guidewire tube 53 defining a guide wire lumen 35 which is shorter than theoverall length of the port tube 12, preferably 3.5 to 10 cm in length.The guide wire tube 53 is preferably an extruded flexible polymer suchas polyethylene and is bonded to the port tube 12 but a suitableadhesive or other bonding process. The port tube 12 in this embodimentis preferably made of a stainless steel braid embedded in a thermosetpolyimide. A dual lumen extrusion is also feasible for thisconstruction. This feature allows the treating physician to retain agrip of the proximal portion of the guide wire 14 while the port tube 12is longitudinally manipulated. In addition, since the guide wire tube 53is less than full length, the extraction lumen 29 is proportionallylarger. Alternatively, the extraction tube 13 may be reduced in sizewithout reducing the size of the extraction lumen 29.

FIG. 5 shows a port tube manifold 37a connected to the proximal end ofport tube 12. The port tube manifold 37a includes a compression sealassembly 38a which releasably and sealably secures to the guide wire 14which extends therethrough. Port tube manifold 37a further includes afluid input port 39, preferably a female luer fitting, which facilitateseasy connection to the pressurized fluid source 15.

Referring to FIG. 6, extraction tube manifold 37b is connected to theproximal end of extraction tube 13. Port tube 12 extends through theextraction tube manifold 37b and can be releasably and sealably securedby compression seal assembly 38b. Extraction tube manifold 37b includesextraction port 41, preferably a female luer fitting, which facilitateseasy connection to the pressurized fluid collector 17. Balloon inflationport 40 is also provided and facilitates easy connection to an inflationdevice (not shown) in order to selectively inflate and deflate theoccluding balloon 27.

Given the preceding detailed description of catheter system 11, amathematical model of the interaction of fluid system 10 with thevasculature will facilitate a description of control system 16. Assumethat the distal end of the catheter system 11 is positioned within avascular lumen. The occluding balloon 27 is inflated proximal to theocclusive material to be removed. The port tube 12 is positioned suchthat the port holes 32 are adjacent the occlusive material. Thepressurized fluid source 15 and the pressurized fluid collector 17 areactivated to establish flow through the port tube 12 and the extractiontube 13. With this arrangement, the operating variables may be definedas follows:

Q_(i) =Volumetric fluid input rate at the distal end of fluid inputlumen 34.

Q_(o) =Volumetric fluid (including removed debris) output rate at thedistal end of fluid extraction lumen 29.

Q_(i) '=Volumetric fluid input rate at the proximal end of fluid inputlumen 34.

Q_(o) '=Volumetric fluid output rate at the proximal end of fluidextraction lumen 29.

P₁ is the pressure proximal to the occlusive material.

P₂ is the pressure adjacent the occlusive material.

P₃ is the intravascular pressure distal of the occlusive material.

P_(o) is the pressure at the proximal end of the fluid extraction lumen29.

P_(i) is the pressure at the proximal end of the fluid input lumen 34.

To maintain a balanced system, Q_(i) must equal Q_(o). This flow balanceis most critical with total occlusions. To maintain a flow patterndirected from the port holes 32 to the extraction lumen 29, P₃ must begreater than P₂ and P₂ must be greater than P₁. Preferably, P₂ is onlyslightly less than P₃, on the order of 0.67 psi.

If P₂ is less than or equal to P₁, the pressurized fluid exiting portholes 32 will either remain stagnant or move in a distal direction, thusincreasing the possibility of distal embolization. If P₃ is less than orequal to P₂, the same result may occur.

If Q_(i) is greater than Q_(o), the potential for distal embolizationand/or vessel rupture increases. Potential causes for the situation inwhich Q_(i) is greater than Q_(o) include a leak or failure in thepressurized fluid collector system 17 and/or a clogged extraction lumen29. If Q_(i) is less than Q_(o), the potential for vessel collapseincreases. The potential causes for Q_(i) less than Q_(o) include a leakor failure in the pressurized fluid source 15 and/or a clogged fluidinput lumen 34.

Tests have demonstrated that the control system 16 may operate solely asa function of the pressure adjacent the occlusive material (P₂). Thecontrol system 16 would maintain P₁ less than P₂ less than P₃ byadjusting the appropriate valves to control pressurized fluid source 15and pressurized fluid collector 17 and thus maintaining fluid flow outthe port holes 32 and into the extraction lumen 29. Pressure P₂ may bemeasured by a small pressure transducer mounted on the distal end of theport tube 12. Examples of suitable pressure transducers can be found oncatheters available from Millar Instruments, Inc., located in Texas.

Although it would be preferable to monitor fluid dynamic parameters atthe distal end of catheter system 11, practical size and costlimitations may be accommodated by locating pressure sensors andvolumetric flow sensors at the proximal end of catheter system 11. Assuch, the possible fluid dynamic parameters to be monitored includeQ_(i) ', Q_(o) ', P_(i) and P_(o). Q_(i) ' equals Q_(i) assuming thatthe pressurized fluid is relatively incompressible at the operatingpressures. However, one cannot assume that Q_(o) ' is equal to Q_(o)because of the possibility of cavitation in the extraction lumen 29.When cavitation occurs, Q_(o) ' is greater than Q_(o). Potential causesfor cavitation include a clogged extraction lumen 29. Because cavitationoccurs before a significant difference in Q_(i) ', and Q_(o) ' isdetectable, it is necessary to monitor pressures at the proximal end ofcatheter system 11. During operation, P_(o) will oscillate in anacceptable pressure window. If P_(o) decreases outside the acceptablepressure window, cavitation is occurring. As stated before, Q_(i) 'remains substantially equivalent to Q_(o) ' for a period of time despitethe occurrence of cavitation in the extraction lumen 29. As such, theimmediate detection of cavitation in extraction lumen 29 is onlypossible by monitoring pressure P_(o).

With reference now to FIG. 1b, the fluid system 10 includes a controlsystem 16 which is operatively connected to the pressurized fluid source15 and the pressurized fluid collector 17. Pressurized fluid source 15is preferably a constant volume pump such as a peristaltic pump, apiston pump, or a diaphragm pump. Pressurized fluid collector 17includes an aspiration pump 18 which is preferably a constant volumepump such as a peristaltic pump, and a fluid collector 19 which ispreferably transparent to allow visualization of the extracted fluid anddislodged occlusive debris. In addition, the entire effluent linedefining the extraction lumen 29 (or only the portion proximal of theextraction tube manifold 37b) may be transparent to allow the treatingphysician to view the removed debris. Control system 16 receives inputfrom pressure sensor 20 which monitors the pressure at the proximal endof extraction lumen 29 (P_(o) in above model). A diverter valve 21 isalso operatively connected to control system 16 and functions to divertpressurized fluid from pressurized fluid source 15 in order to controlthe volumetric flow rate into fluid input lumen 34.

In this embodiment, the control system 16 maintains balanced volumetricflow (i.e., Q_(i) '=Q_(o) ' and Q_(i) =Q_(o)). In the event that afailure or leak in the pressurized fluid collector 17 occurs or in theevent that extraction lumen 29 becomes clogged (i.e. Q_(i) >Q_(o)),control system 16 actuates diverter valve 21 so as to reduce Q_(i) tocome into equilibrium with Qo. A means to immediately detect a cloggedextraction lumen 29 causing cavitation is provided by pressure sensor 20which detects an decrease in the pressure (P_(o)) at the proximal end ofextraction lumen 29 which is an indicator of cavitation. Control system16 responds to an increase in pressure as detected by pressure sensor 20in the same way it responds to Q_(i) '>Q_(o) ' as discussed above. Inthe event that a failure or leak in the pressurized fluid source 15occurs, or in the event that fluid input lumen 34 becomes clogged (i.e.,Q_(i) <Q_(o)), control system 16 shuts down pressurized fluid source 15and pressurized fluid collector 17.

With reference now to FIG. 1c, the fluid system 10 is substantially thesame as that which is shown in FIG. 1b with the following exceptions.Control system 16 is operatively connected to an input flow sensor 23, amodulator valve 24 and a shut-off valve 25 which are positioned betweenthe pressurized fluid source 15 and the fluid input port 39. An outputsensor 22 is also operatively connected to the control system 16 and ispositioned between the extraction port 41 and the pressurized fluidcollector 17. Flow sensors 22 and 23 are preferably ultrasonicvolumetric flow sensors such as Model No. 6X available from TransonicSystems, Inc., located in New York. Flow modulator valve 24 and shut-offvalve 25 are preferably of the solenoid type. Thus, the fluid dynamicparameter sensors (22, 23) and the flow control valves (24, 25) areelectronically controlled by control system 16. If Q_(o) ' as detectedby output flow sensor 22 is less than Q_(i) ' as detected by input flowsensor 23, control system 16 proportionately closes modulator valve 24so as to bring Q_(i) ' into balance with Q_(o) '. If Q_(o) ' is greaterthan Q_(i) ', control system 16 proportionately opens modulator valve 24so as to bring Q_(i) ' into equilibrium with Q_(o) '. In the event thatQ_(o) ' is greater than Q_(i) ' and the modulator valve 24 is fullyopen, control system 16 actuates shut-off valve 25 and stops pressurizedfluid source 15 and pressurized fluid collector 17 to prevent vesselcollapse. As in the fluid system 10 described with reference to FIG. 1b,a pressure sensor (not shown in FIG. 1c) may be incorporated adjacentoutput flow sensor 22 to detect cavitation in extraction lumen 29 asdiscussed above. The control system 16 would be operatively connected tothe pressure sensor and respond substantially as described withreference to the pressure sensor as shown in FIG. 1b.

Modulator valve 24 is preferably of the solenoid type and is shown inFIG. 7. Referring to FIG. 7, the solenoid modulator valve 42 includes avalve housing 43 and a solenoid shaft 44 slidably disposed in acylindrical chamber 51. The chamber 51 in valve housing 43 furtherdefines a valve seat 45. The solenoid shaft 44 defines a valve head 46at the end of the shaft 44 disposed in the chamber 51. The valve housing43 further includes a fluid input port 48 and a fluid output port 47.The fluid output port 47 is in fluid communication with the valve seat.The fluid input port 48 is in fluid communication with the valve seat(and thus the fluid output port 47) only when the valve head 46 is notpositioned in valve seat 45. The valve seat 45 and the valve head 46 areshaped so as to provide a substantially fluid seal when positionedagainst each other. The solenoid modulator valve 42 further includes abiasing spring 49 disposed between the solenoid head 52 and the valvehousing 43. One end of the spring 49 is rigidly connected to thesolenoid head 52 and the other end is rigidly connected to the valvehousing 43. When the solenoid coil is not activated (i.e. relaxedstate), the biasing spring 49 retains the solenoid shaft 44 and valvehead 46 in a closed valve position. The valve housing 43 furtherincludes a plurality of recesses 50 for ball detent. The ball detent(not shown) provide a means to releasably secure the solenoid modulatorvalve 42 in a solenoid coil (not shown). The solenoid coil is actuatedby a desired electromotive force, preferably 768 watts, andcorresponding driver circuit which in turn longitudinally displaces thelow mass solenoid head 52, preferably 2.5 grams in combination withsolenoid shaft 44. The high power driver circuit and the low masssolenoid head 52 allow the modulator valve 42 to operate at very highfrequencies. The longitudinal actuation of solenoid head 52 causes thesolenoid shaft 44 and the valve head 46 to move in and out of valve seat45. Thus, as the solenoid head 52, solenoid shaft 44, and the valve head46 longitudinally oscillate, flow is permitted between fluid input port48 and fluid output port 47 as a function of the period of time that thevalve head 46 is not positioned against valve seat 45. The amplitude andfrequency of oscillation can be varied by means of an appropriate drivercircuit (not shown) operatively connected to the solenoid coil. Thesolenoid coil is preferably driven by a switching solenoid drivercircuit with a frequency between 0.25 cycles per second and 500 cyclesper second. Flow is thus modulated by changing the solenoid off-time andon-time. The utilization of biasing spring 49 allows the solenoid coilto be unidirectional and also allows for high operating frequencies.

A second preferred fluid system 10 utilizes a double-acting piston pump54 as seen in FIG. 8. The double-acting piston pump 54 includes a pumphousing 55. Pump housing 55 further includes housing feet 69 forsecurely placing the double-acting piston pump 54 on a level surface.Mechanical grounds 56 shown in FIG. 8 and are intended to schematicallyreflect a fixed position of components relative to the pump housing 55.Mounted inside pump housing 55 is a stepper motor 66 which rotatespulley 67 which in turn rotates ball screw rotating nut and pulley 64 byway of belt 68. The ball screw rotating nut and pulley 64 axiallydisplaces the threaded shaft 63 relative to the thrust bearing 65 whichis mechanically grounded to the housing 65. The threaded shaft 63 inturn is connected to an outlet piston 61a and an inlet piston 61b. Aroller pin (not shown) connected to the pistons 61a, 61b and slidablylocated in a guide slot (not shown) which mechanically grounded to thehousing 65 may be used to prevent the pistons 61a, 61b from rotating dueto the frictional interface with the threaded shaft 63. The inlet piston61b is sealably and slidably positioned inside inlet piston chamber 62b,utilizing an O-ring seal 60. Fluid is pulled into the inlet pistonchamber 62b by way of inlet port 58. Similarly, outlet piston 61a isslidably positioned inside outlet piston chamber 62a and is sealed byhigh pressure O-ring or compression seal 59. The pressure seals 59 and60 may alternatively be disposed on the pistons 61a and 61b. Pressurizedfluid exits outlet piston chamber 62a by way of outlet port 57. Outletport 57 is in turn connected to the fluid input lumen 34 by way of theport tube manifold 37a. Similarly, inlet port 58 is fluidly connected tothe extraction lumen 29 by way of the extraction tube manifold 37b.

Inlet piston 61b is preferably made of a polymer and is disposable aftera selected number of procedures for sanitary purposes. The inlet chamber62b is also made of a disposable polymer material and isdisposed/replaced along with piston 61b. Outlet piston 61a, outletpiston chamber 62a, the pump housing 55 and associated internalcomponents (56, 63-69) are made of materials conventional in the art(e.g. stainless steel) and are intended to be reusable. The pistonchambers 62a and 62b are approximately 1 liter in volume which renderthem suitable for approximately four procedures before replacement orresetting to starting position becomes necessary. A bio-block filter(not shown), which are known in the art, may be utilized to maintainsterility of the outlet piston 61a and the outlet piston chamber 62a.The bio-block filter would be fluidly connected to the outlet port 57.

The double-acting piston pump 54 offers several advantages over otherconstant volume pumps. For example, the double-acting piston pump 54does not require a microprocessor control system. The pressure iscontrolled by adjusting the torque of the stepper motor 66. When theselected pressure is exceeded and thus the selected torque is exceeded,the stepper motor simply stops rotating and stops movement of outletpiston 61a. Although the outlet piston stops moving a residual pressurewill cause a small amount of fluid to egress out of the outlet port 57for a short period of time after the stepper motor 66 stops rotating. Tooffset this residual pressure, a suitable electronic or manual on/offvalve and vent (not shown) is utilized between the outlet port 57 andthe port tube manifold 37a. Thus, when the pressure inside outlet pistonchamber 62a exceeds a certain amount as specified by the torque set onthe stepper motor 66, the stepper motor shuts down, the valve shuts offand vents excess pressure. A similar valve may be employed in line withthe input port 58 to bring residual pressures in the inlet chamber 62bto ambient pressure. As with the other control systems describedpreviously, a pressure transducer located between the inlet port 58 andthe extraction manifold 37b may be utilized to detect cavitation. Inaddition, it is contemplated that the pressure adjacent the distal endof the port tube 12 as measured by a suitable pressure transducer wouldprovide sufficient information to operate the entire system. Morespecifically, if the measured pressure adjacent the distal end of theport tube 12 falls outside a predetermined acceptable window, the doubleacting piston pump 54 stops and the valve (preferably a solenoid valve)turns off and vents the system pressure to ambient pressure. The systemmay then be restarted by actuating the appropriate switches such as afoot pedal switch.

The stepper motor 66 is controlled by a conventional control circuit(not shown) which adjusts torque and speed. The control circuit alsoincludes a switch to allow the treating physician to turn thedouble-acting piston pump 54 on and off, in addition to forward andreverse. The stepper motor 66 may be reversed to return the pistons 61a,61b to their initial position. However, because the piston chambers 62a,62b are relatively large in capacity (preferably 1 liter), the pitons61a, 61b need not be reset to their starting position until after aboutfour procedures.

Another advantage of the double-acting piston pump 54 over alternativeconstant volume pumps is that the pump 54 is relatively quiet, whichallows the treating physician to focus on the patient and the procedureas a whole. In view of the critical nature of coronary intervention, itis preferable to have as few distractions as possible in the cardiaccath lab.

In practice, the fluid system 10 is used in the following manner. First,a guide wire 14 is inserted into the guide wire lumen 35 such that theguide wire 14 extends out the distal end of the catheter system 11. Thecatheter system 11 and the guide wire 14 are then inserted into the bodyeither directly into the vasculature or by way of a guide catheter. Thedistal end of the extraction tube 13 is positioned proximally of theocclusive material to be removed. The occluding balloon 27 is theninflated to isolate a portion of the vasculature distal thereof. Thepressurized fluid source 15 and the pressurized fluid collector 17 arethen activated in combination with control system 16. As pressurizedfluid exits out port holes 32 by way of fluid input lumen 34, thepressurized fluid dislodges and suspends occlusive material. Theocclusive material is then removed by way of extraction lumen 29 and iscollected in pressurized fluid collector 17. The port tube 12 can bemoved independently of aspiration tube 13 in order to remove occlusivematerial without the need to relocate the aspiration tube 13 and theoccluding balloon 27. In the event that the extraction lumen 29 becomesclogged, the port tube 12 can be pulled back such that the port holes 32are located inside the extraction lumen 29. Thus, the pressurized fluidexiting port holes 32 cause the clogged material to be swept towards thepressurized fluid collector 17. The port tube 12 can then be re-advanceddistally of the distal end of extraction tube 13 and occluding balloon27 to continue the process of removing occlusion material.

Prior to use, the catheter system 11 must be purged in order to removeair from the extraction lumen 29 and the fluid input lumen 34. This maybe accomplished by inserting the distal end of the catheter system 11such that the port holes 32 are located in a reservoir of fluid. Thesystem is then turned on such that pressurized fluid circulates throughthe fluid input lumen 34 and fluid from the fluid reservoir is pulledinto the extraction lumen 29. After running the fluid system 10 for ashort period of time, the catheter system 11 is substantially void ofgas. After the fluid system 10 is purged, the pressurized fluid source15, the pressurized fluid collector 17 and the associated control system16 must be calibrated in order to correctly maintain balanced flow. Withthe distal end of the catheter system 11 in a small vial with a luerfitting sealably connectable thereto, the pressurized fluid source 16,the pressurized fluid collector 17, and the control system 16 areinitiated. The height of the fluid in the vial is monitored and acalibration dial is adjusted on the control system 16 to maintainbalanced flow as indicated by a steady height of fluid in the vial. Oncethe height of the fluid in the vial is constant, the fluid system 10 iscalibrated with Q_(i) equal to Q_(o).

While the specification describes the preferred designs, materials,methods of manufacture and methods of use, those skilled in the art willappreciate the scope and spirit of the invention with reference to theappended claims.

What is claimed is:
 1. A fluid system for the extraction of vascularoccluding material, comprising:a. an elongate catheter shaft having aproximal end and a distal end, the elongate shaft including a fluidinput tube and a fluid extraction tube, the fluid input tube beinglongitudinally movable relative to the fluid extraction tube; b. thefluid input tube defining a fluid input lumen; c. the fluid extractiontube defining a fluid extraction lumen; d. a pressurized fluid sourceconnected to the proximal end of the shaft and in fluid communicationwith the fluid input lumen; e. a pressurized fluid collector connectedto the proximal end of the shaft and in fluid communication with theextraction lumen; f. a nozzle attached to the distal end of the fluidinput tube and in fluid communication with the fluid input lumen; g. acontrol system operatively connected to the pressurized fluid source andthe pressurized fluid collector; and h. a fluid dynamic sensorpositioned in either the fluid input lumen or the fluid extractionlumen, the fluid dynamic sensor operatively connected to the controlsystem.
 2. A fluid system as in claim 1, wherein the fluid dynamicsensor ish. positioned between the fluid extraction lumen and thepressurized fluid collector.
 3. A fluid system as in claim 1, whereinthe fluid dynamic sensor isi. positioned between the fluid input lumenand the pressurized fluid source.
 4. A fluid system as in claim 2,further comprising:i. a valve positioned between the fluid input lumenand the pressurized fluid source, the valve being controlled by thecontrol system as a function of the fluid dynamic sensor.
 5. A fluidsystem as in claim 1, wherein the fluid input tube is coaxially disposedwithin the fluid extraction tube.
 6. A fluid system as in claim 5,wherein the fluid extraction tube includes an occluding balloon locatedadjacent the distal end of the fluid extraction tube.
 7. A fluid systemas in claim 6, wherein the fluid extraction tube includes a laterallyfacing window located distally of the occluding balloon.
 8. A fluidsystem as in claim 1, wherein the fluid input lumen further defines aguide wire lumen and includes a guide wire extending therethrough.
 9. Afluid system as in claim 8, wherein the fluid input tube includes alongitudinal slit which the guide wire may pass through.
 10. A fluidsystem as in claim 8, wherein the fluid input tube includes an exit portwhich the guide wire may pass through, the exit port located distal ofthe proximal end of the fluid input tube.
 11. A fluid system as in claim1, wherein the nozzle includes at least one port hole which is directedoutwardly.
 12. A fluid system as in claim 11, wherein the port hole isdirected at least partially proximally.
 13. A fluid system as in claim11, wherein the port hole is directed at an angle to a lateral tangentline on an outer surface of the fluid input tube.
 14. A fluid system asin claim 12, wherein the port hole is directed at an angle to a lateraltangent line on an outer surface of the fluid input tube.
 15. A fluidsystem as in claim 11, wherein the nozzle includes a plurality of portholes arranged in a plurality of circumferential rows.
 16. A fluidsystem for the extraction of vascular occluding material, comprising:a.an elongate extraction tube having a proximal end, a distal end, and anextraction lumen extending therethrough; b. a fluid input tubecoextending with the extraction tube and longitudinally movable relativethereto, the fluid input tube having a proximal end, a distal end, and afluid input lumen extending therethrough; c. a pressurized fluid sourceconnected to the proximal end of the fluid input tube and in fluidcommunication with the fluid input lumen; d. a pressurized fluidcollector connected to the proximal end of the extraction tube and influid communication with the extraction lumen; e. a guide wirecoextending with the fluid input tube and longitudinally movablerelative thereto, and; f. a nozzle connected to the distal end of thefluid input tube and in fluid communication with the fluid input lumen.17. A fluid system as in claim 16, wherein the nozzle includes at leastone port hole which is directed outwardly.
 18. A fluid system as inclaim 17, wherein the port hole is directed at least partiallyproximally.
 19. A fluid system as in claim 17, wherein the port hole isdirected at an angle to a lateral tangent line on an outer surface ofthe fluid input tube.
 20. A fluid system as in claim 18, wherein theport hole is directed at an angle to a lateral tangent line on an outersurface of the fluid input tube.
 21. A fluid system for the extractionof vascular occluding material, comprising:a. an elongate catheter shafthaving a proximal end, a distal end, a longitudinal axis, and an outsidediameter; b. a fluid input lumen extending through the shaft; c. anextraction lumen extending through the shaft; d. a pressurized fluidsource connected to the proximal end of the shaft and in fluidcommunication with the fluid input lumen; e. a pressurized fluidcollector connected to the proximal end of the shaft and in fluidcommunication with the extraction lumen; f. a nozzle attached to thedistal end of the shaft and in fluid communication with the fluid inputlumen, and; g. at least one port hole located about the circumference ofthe nozzle, the port hole having an axis, the port hole directedlaterally such that the axis of the hole is at an acute proximallyfacing angle relative to the longitudinal axis of the shaft and definesa spray diameter which is greater than the outside diameter of thecatheter shaft adjacent to the nozzle, the nozzle and port hole beinglocated distally on the shaft such that the spray diameter engages theoccluding material before the distal end of the shaft substantiallytraverses the occluding material.
 22. A fluid device as in claim 21,wherein the pressurized fluid source is a constant volume pump.
 23. Afluid device as in claim 21, wherein the pressurized fluid collector isa constant volume pump.
 24. A fluid device as in claim 21, wherein thepressurized fluid source operates at a pressure substantially within therange of 1 to 2500 psi.
 25. A fluid device as in claim 21, wherein thepressurized fluid source operates at a pressure substantially within therange of 500 to 1500 psi.
 26. A method of extracting vascular occludingmaterial wherein the vasculature has a first pressure zone with a firstpressure proximal to the occluding material, and a second pressure zonewith a second pressure adjacent the occluding material, the methodcomprising the steps of:i. providing a fluid extraction system,comprising:a. an elongate catheter shaft having a proximal end, a distalend, a fluid input lumen extending therethrough, and an extraction lumenextending therethrough; b. a pressurized fluid source connected to theproximal end of the shaft and in fluid communication with the fluidinput lumen; c. a pressurized fluid collector connected to the proximalend of the shaft and in fluid communication with the extraction lumen;d. a nozzle attached to the distal end of the shaft and in fluidcommunication with the fluid input lumen; e. a control system whichcontrols the pressurized fluid source and the pressurized fluidcollector as a function of at least one of the first or secondpressures; and f. at least one port hole located about the circumferenceof the nozzle, the port hole having an axis, the port hole directedlaterally such that the axis of the hole is at an acute proximallyfacing angle relative to the longitudinal axis of the shaft and definesa spray diameter which is greater than the outside diameter of thecatheter shaft adjacent to the nozzle, the nozzle and port hole beinglocated distally on the shaft such that the spray diameter engages theoccluding material before the distal end of the shaft substantiallytraverses the occluding material, ii. inserting the catheter into thevasculature; and iii. extracting vascular occluding material from thevasculature.
 27. A method of extracting vascular occluding material asin claim 26, wherein the control system correlates the first pressure toa first measured fluid dynamic parameter in the extraction lumen.
 28. Amethod of extracting vascular occluding material as in claim 27, whereinthe control system correlates the second pressure to a second measuredfluid dynamic parameter in the fluid input lumen.
 29. A method ofextracting vascular occluding material as in claim 26, wherein thecontrol system maintains the first pressure less than the secondpressure.
 30. A method of extracting vascular occluding material as inclaim 26, wherein the control system maintains the second pressuregreater than the first pressure.
 31. A method of extracting vascularoccluding material as in claim 27, wherein the control system maintainsequal volumetric flow between the fluid input lumen and the extractionlumen.
 32. A method of using a fluid system for the extraction ofvascular occluding material wherein the device comprises an elongatecatheter shaft having a proximal end and a distal end, a fluid inputlumen extending through the shaft, an extraction lumen extending throughthe shaft, a pressurized fluid source connected to the proximal end ofthe shaft and in fluid communication with the fluid input lumen, apressurized fluid collector connected to the proximal end of the shaftand in fluid communication with the extraction lumen, a nozzle attachedto the distal end of the shaft and in fluid communication with the fluidinput lumen, and a control system operatively connected to thepressurized fluid source and the pressurized fluid collector, thecontrol system controlling the pressurized fluid source and thepressurized fluid collector as a function of fluid dynamic parameters inthe fluid input lumen and the fluid extraction lumen, the method of usecomprising the steps of:i. inserting the guide wire into the fluid inputtube; ii. advancing the guide wire, the fluid input tube and theextraction tube into a vascular lumen; iii. positioning the distal endof the extraction tube proximal to an occlusion to be removed; iv.positioning the distal end of the fluid input tube adjacent theocclusion to be removed; v. activating the pressurized fluid source andthe pressurized fluid collector; and vi. longitudinally sliding thefluid input tube relative to the extraction tube.
 33. A method of usinga fluid system as in claim 32, comprising the additional step of:vii.deactivating the pressurized fluid source and the pressurized fluidcollector if the volumetric flow in the extraction lumen is notsubstantially equal to the volumetric flow in the fluid input lumen. 34.A method of using a fluid system as in claim 32, comprising theadditional step of:vii. longitudinally sliding the fluid input tube in aproximal direction such that the nozzle enters the extraction lumen. 35.A method of using a fluid system for the extraction of vascularoccluding material wherein the device comprises an elongate extractiontube having a proximal end, a distal end, and an extraction lumenextending therethrough; a fluid input tube coextending with theextraction tube and longitudinally movable relative thereto, the fluidinput tube having a proximal end, a distal end, and a fluid input lumenextending therethrough; a pressurized fluid source connected to theproximal end of the fluid input tube and in fluid communication with thefluid input lumen; a pressurized fluid collector connected to theproximal end of the extraction tube and in fluid communication with theextraction lumen; a guide wire coextending with the fluid input tube andlongitudinally movable relative thereto, and; a nozzle connected to thedistal end of the fluid input tube and in fluid communication with thefluid input lumen, the method of use comprising the steps of:i.inserting the guide wire into the fluid input tube; ii. advancing theguide wire, the fluid input tube and the extraction tube into a vascularlumen; iii. positioning the distal end of the extraction tube proximalto an occlusion to be removed; iv. positioning the distal end of thefluid input tube adjacent the occlusion to be removed, and; v.activating the pressurized fluid source and the pressurized fluidcollector.
 36. A method of using a fluid system as in claim 35,comprising the additional step of:vi. longitudinally sliding the fluidinput tube relative to the extraction tube.
 37. A method of using afluid system as in claim 36, comprising the additional step of:vii.deactivating the pressurized fluid source and the pressurized fluidcollector if the volumetric flow in the extraction lumen is notsubstantially equal to the volumetric flow in the fluid input lumen. 38.A method of using a fluid system as in claim 36, comprising theadditional step of:vii. longitudinally sliding the fluid input tube in aproximal direction such that the nozzle enters the extraction lumen. 39.A method of using a fluid system as in claim 38, comprising theadditional step of:viii. longitudinally sliding the fluid input tube ina distal direction such that the nozzle exits the extraction lumen.